Análise dos efeitos de carbonatação na resistência ao esmagamento de filtros granulares

Abstract

It is common to use permeable filters in hydraulic works, in order to control the passage of percolated materials. Filtration systems can be executed, for example, with granular materials, geotextile material and/or artificial sand, which is manufactured in the laboratory through crushed or ground rocks, until the granulometry indicated by standard is reached. That said, it is necessary to know the physical, chemical and mechanical characteristics, as well as the degree of alteration and alterability of the rock to be used. In granular filters used in drainage works of roads, dams and embankments, the oscillation of the water level can promote saturation cycles and alter the geotechnical parameters of the rock material over the time of operation. It should be noted that the rocky material used in granular filters is in a constant process of crushing, which tends to alter the granulometry of the material, which can cause clogging of the filters or even loading particles in addition to the water, making the filter inefficient. In the present work, the influence of accelerated cycling with water saturated by carbon dioxide on the crushing strength of basalt aggregates was evaluated, in a typical granulometry of granular filters. Three variations of basalt were evaluated, differentiated by the presence of microtonsils and matrix placement. It was found that the presence of expansive clay minerals contained in the microtonsils has an influence on the crush resistance of basalt due to the carbonation reaction consequent to the reaction of the minerals with the CO2 contained in the percolated water. Thus, it is necessary to know the intrinsic characteristics of the material used as a granular filter.